1. Field of the Invention
This invention relates to the sealing of reciprocable members with respect to the cavities in which they are reciprocable.
2. Description of Prior Art
In many types of equipment and machinery the situation arises in which a member which is reciprocably-movable in a cavity is exposed to a first, higher fluid pressure on its first side and to a second, lower fluid pressure on its second side. This pressure differential produces a tendency for leakage to occur between the reciprocable member and the cavity wall and for fluid to flow from the first side of the piston to the second. The higher the pressure differential, the greater is this tendency. The leakage is a particular disadvantage if reasons exist for avoiding contamination of the second fluid by the first fluid, or other mixing of fluids. As an example, leakage is highly undesirable when the first fluid contains abrasive material which is to be excluded from the second fluid in order to protect other parts of the equipment with which the second fluid is in communication.